The nutritional quality of pasta, and often its taste and texture, generally depend upon the flour used to form the pasta. For instance, pasta made with whole grain flours, such as whole wheat pasta, is nutrient-rich because it contains bran and germ. However, the whole grain flour pasta generally does not have the textural characteristics desired by the consumer and its dough is difficult to process into the desired pasta shapes. Pasta formulas containing large amounts of protein, such as 20 percent or more, make the pasta dough hard to extrude and produces a product exhibiting rubbery characteristics or an extremely firm texture.
Most pasta, as a result, is made with durum wheat, which is hard wheat with increased levels of highly functional protein (gluten). Typically flours used to produce pasta have about 10 to about 13 percent protein. Durum wheat is desired for pasta because it makes dough that sticks together well and holds its shape, which are features preferred for pasta manufacture. More importantly, the durum wheat flour also produces pasta having a textural characteristic desired by the consumers—a firm, yet chewy pasta generally characterized as “al dente.” Most high quality pasta is made with durum wheat semolina, which is a more coarsely ground wheat flour. However, in these flours, the germ and bran have been removed and, therefore, the fiber and nutritional values are generally lower than the whole grain flours.
In today's weight- and health-conscience society, high protein and low carbohydrate foods are often desired as part of a modified diet that may result in weight loss. As a result, attempts have been made to modify traditional foods with higher levels of protein and lower levels of carbohydrates to satisfy this consumer demand. However, such food reformulation is often difficult because, while the reformulated food may have higher levels of protein and lower levels of carbohydrates, it may not have the mouthfeel or organoleptic properties of conventional food. To achieve consumer acceptance of the nutritionally enhanced products, it is preferred to achieve textural, mouthfeel, and organoleptic properties similar to the conventional foods they are replacing.
Formulating nutritionally enhanced pasta, such as high-protein and low-carbohydrate pasta, is no exception. Increasing the protein levels in pasta, either through fortification with other sources of protein (i.e., soy protein, wheat gluten, or dairy proteins) or by using higher protein flours, is wrought with difficulties. Prior attempts at producing a high protein, low carbohydrate pasta through the selection of specific ingredients generally produces pasta that exhibits chewy and rubbery mouthfeel characteristics, which are not typically desired by the consumer.
Moreover, high levels of highly functional protein (i.e., levels greater than about 13 percent in the raw materials) in pasta dough are also difficult to process. Protein sources such as gluten, wheat protein isolates, and soy protein isolates, when used to manufacture pasta dough, would fall in this difficult-to-process category. For instance, such high levels of protein in pasta dough are often more difficult to extrude, particularly at very high levels of incorporation, such as levels greater than about 18 to about 20 percent protein in the dough. During pasta manufacture, gluten in pasta dough absorbs water and swells to form a cross-linked network, which is typically referred to as gluten development. However, higher levels of gluten in pasta dough absorb higher levels of water that can result in a rapid and extensive gluten development to form pasta dough that is highly elastic, and which has a tendency to exhibit a property called “balling” during processing. Highly elastic pasta dough is very difficult to process using extruders. For instance, very elastic dough obtained through strong protein-protein interactions will result in high press pressures and will be hard to process. Moreover, the dough will also have a tendency to ball or adhere to the paddles or other surfaces of the mixer. Furthermore, if the material has a strong tendency to ball, such material will not feed properly from the blender into the press, causing intermittent flow with associated defective product or creating extremely high pressures at the press with problems in process control.
On the other hand, fortifying pasta dough with other low functionality proteins or using alternative flours to increase the protein levels in the pasta also does not form a satisfactory product. For example, pasta dough has previously been processed with dairy or whey proteins and/or corn, rice, or soy flour to achieve high protein pasta. However, these protein sources generally have poor network forming characteristics and, therefore, do not create desirable pasta. Levels of these low functionality proteins, especially above about 5 percent, typically form dough that does not produce the desired texture of a semolina product because of poor ability to create a strong protein network.
Accordingly, there is a desire for nutritionally enhanced pasta with increased protein levels that can be processed through traditional pasta manufacturing equipment that also exhibits textural, mouthfeel, and organoleptic properties of conventional pasta.